1. Field of the Invention
This invention relates to an apparatus for puncturing a vehicle tire. More particularly, the present invention relates to an improved portable and retractable barrier strip for puncturing a fleeing vehicle""s tires.
2. State of the Art
The need to effectively and safely stop a fleeing vehicle without damage to non-offending vehicles or harm to people involved has long been a concern for law enforcement officials. Consequently portable spike barrier strips have been developed for deployment across the anticipated path of a fleeing vehicle to puncture the vehicle""s tires and more quickly end potentially dangerous car chases. Examples of prior art spike barrier strips are disclosed in U.S. Pat. Nos. 4,382,714 and 4,995,756.
Unfortunately, these known barrier strips have several drawbacks. For example, in order to stop a fleeing vehicle and yet avoid collateral damage to non-offending vehicles that may be using the same path, these prior-art barrier strips must be deployed in the path of the vehicle either (1) when the area is tightly controlled or (2) only immediately prior to the fleeing vehicle passing. Otherwise, damage to any non-offending vehicles traveling the same path is almost always certain because the sharp, tire-puncture spikes remain exposed at all times during deployment of the barrier.
To solve these and other problems, retractable barrier strips have been developed, such as disclosed in U.S. Pat. No. 5,507,588 to Marts, et al, which disclosure is included herein by reference. The ""588 barrier strip comprises a plurality of barrier blocks interconnected in a linear fashion, each barrier block having retractable spikes disposed therein, and designed to remain relatively stable and motionless while a vehicle tire rolls thereover. In its preferred embodiment, a shaft is rotatably disposed in each barrier block, the shaft removably, pivotally, and rotatably interconnecting each barrier block to the next adjacent barrier block to form the barrier strip. With the pivotal connection of adjacent barrier blocks, the barrier strip may be rolled up for easy retrieval, portability, and storage purposes, and simply unrolled to an extended position for deployment and use.
The spikes, preferably hollow, are removably disposed in the shaft, and the shaft may be rotated to arm the spikes for puncturing a vehicle tire, and counterrotated to retract the spikes into a hollow bed for not puncturing a tire. When the spikes are retracted, a vehicle tire may roll over the barrier block without damage. A rotating mechanism is provided to allow a user to rotate the interconnected shafts of all barrier blocks, to thereby simultaneously extend or retract all spikes of all blocks in the barrier strip.
The retractable spikes allow for deployment personnel to easily and safely deploy the strip at a convenient time, with the spikes in a retracted position. The spikes remain in the retracted position, allowing non-offending and law enforcement vehicles to drive over the stable and non-moving barrier blocks without damage, until a fleeing vehicle nears. At that point, the spikes may be safely activated by a law enforcement officer to an armed position from a remote location for maximum safety. Following puncture of the tires of the target vehicle, the spikes may then be retracted to allow other vehicles to again follow the same path without damage.
While this retractable barrier strip has solved many of the problems of the prior art, there are some concerns which it does not currently address. For example, the pivotal connection of the shafts of adjacent barrier blocks in the ""588 device does not adequately allow for irregular road surfaces and curves in all cases. This configuration also tends to subject the shafts to relatively high stresses when in use, which reduces the durability and reliability of the device. For example, when a vehicle strikes the barrier strip, it imparts a lateral deflecting force which tends to twist adjacent barrier blocks about their pivotal connection in a horizontal plane. This horizontal twist subjects the pivotal connection of the shafts to very high stresses, and leads to premature failure of the connection. It would therefore be desirable to have a retractable barrier strip which incorporates a more robust pivotal connection between blocks while still allowing easy rotation and pivoting of connected shafts. It would also be desirable to have a retractable barrier strip which more adequately resists stress at the connection point between the shaft of adjacent barrier blocks, while still allowing for irregularities in roadway surfaces and road curvature.
Additionally, in the prior art retractable barrier strip, the hinge connection of adjacent barrier blocks allows the barrier strip to be bent or rolled up backwards, with the top of the barrier blocks facing out, rather than in. This situation presents the possibility of the spikes extending out from the rolled up unit, potentially causing property damage or injury to users. It would therefore be desirable to have a retractable barrier strip in which the pivotal connection of adjacent blocks prevents significant back bending of adjacent blocks, thus allowing the barrier strip to be rolled up in only one orientation with the tops of the blocks facing inwardly.
The barrier strip of the ""588 patent also utilizes a two-cable push-pull system for rotating the shaft to extend or retract the spikes. This system is complicated and cumbersome, and presents reliability and maintenance problems. Because the linearly moving cables extend the entire length of the barrier strip, they encounter frictional resistance along their entire length. Consequently, the force required to pull the cable and rotate the shafts is considerable, and this force increases as the length of the barrier strip increases. Additionally, with the prior push-pull cable system, arming or disarming the spikes requires a specific movement on the part of the operator. It would therefore be desirable to have a retractable barrier strip with a simpler, more reliable spike extension and retraction mechanism for remote arming of the spikes, and one which automatically retracts the spikes when released, rather than requiring a separate motion to retract them.
Moisture and debris buildup in the spike hollow bed of the ""588 invention is also an occasional problem. With wind, rain, and vehicle motion, dirt, sand, and other debris is easily swept into the hollow-bed for surrounding the spikes. While water quickly runs out or evaporates from the hollow-bed, the sand, dirt, etc. tends to stay, causing excess wear to the device and possibly interfering with its proper operation. It would therefore be desirable to have a retractable barrier strip with means for drainage around the spikes, and means for keeping the rotational area free from mud, dirt, and debris.
It is therefore an object of the present invention to provide a retractable barrier strip having a universal-joint connection between shafts of adjacent barrier blocks to reduce stress at the connection point, and to more fully allow for irregularities in roadway surfaces and road curvature.
It is another object of this invention to provide a retractable barrier strip having adjacent barrier blocks hingedly connected to each other for a stronger connection that also substantially disallows back bending.
It is another object of this invention to provide a retractable barrier strip having a simple, single cable system for rotating the shaft to extend the spikes.
It is another object of this invention to provide a retractable barrier strip having a simple, single cable spike extension system, which automatically retracts the spikes when released, rather than requiring a separate motion to retract them.
It is another object of this invention to provide a retractable barrier strip having a remotely controlled, power activated spike extension system, which allows the user to extend or retract the spikes from a greater distance away from the barrier strip.
It is yet another object of this invention to provide a retractable barrier strip having means for drainage around the spikes, and for keeping the rotational area free from mud, dirt, and debris.
It is still another object of this invention to provide a method of deploying a portable barrier strip across the path of a target vehicle to puncture at least one of the vehicle""s tires.
The above and other objects are realized in a portable barrier strip having retractable spikes disposed in a plurality of interconnected tire mountable barrier blocks. The spikes are disposed in a rotatable shaft disposed within each barrier block, and the shafts of adjacent barrier blocks are advantageously interconnected by a universal-joint to reduce stress at the connection point, and to more fully allow for irregularities in roadway surfaces and road curvature. The spikes are extendable by rotating the connected shafts of the plurality of barrier blocks by means of a single flexible cable or xe2x80x9cflexshaft xe2x80x9d housed in a flexible, cylindrical tube. The flexshaft is spring-loaded and incorporates a ratchet mechanism with a release lever such that it may be rotated to arm or extend the spikes, and by moving the release lever, will automatically retract the spikes under the spring force, rather than requiring a separate motion to retract them. Alternatively, the flexshaft may be rotated by an electrical motor or other power means, which may be controlled by direct wire or through a wireless remote.
The barrier blocks are hingedly connected to each other, rather merely having the rotatable shafts of adjacent blocks pivotally connected, which provides a more robust connection, and also limits the amount of back bending, thus providing added protection for the rotatable shaft pins and increased overall pad stability. In the preferred embodiment, each block has a first end and a second end. The first end comprises a pair of widely spaced hinge loops, and the second end comprises a pair of more closely spaced hinge loops. The hinge loops of the first end of one block mate with the hinge loops of the second end of an adjacent block, and are interconnected by a hinge pin which allows rotation of connected blocks relative to each other about a horizontal axis that is generally perpendicular to the axis of the spike shaft.
The hinge loops are also configured with an end face which interferes with backward rotation of adjacent blocks so as to freely allow pivoting of adjacent barrier blocks in a manner which draws top surfaces of adjacent blocks together, but substantially prevents pivoting of the hinge means which draws the bottom surfaces of adjacent blocks together. This feature ensures that the barrier strip can only be rolled up with the top surfaces of blocks facing inward.